Make tincctl robust against dropped control connections.

diff --git a/src/tincctl.c b/src/tincctl.c
index eaf676d..0d773e4 100644 (file)
--- a/src/tincctl.c
+++ b/src/tincctl.c
@@ -687,8 +687,19 @@ static bool remove_service(void) {
 #endif
 
 static bool connect_tincd(bool verbose) {
-       if(fd >= 0)
-               return true;
+       if(fd >= 0) {
+               fd_set r;
+               FD_ZERO(&r);
+               FD_SET(fd, &r);
+               struct timeval tv = {0, 0};
+               if(select(fd + 1, &r, NULL, NULL, &tv)) {
+                       fprintf(stderr, "Previous connection to tincd lost, reconnecting.\n");
+                       close(fd);
+                       fd = -1;
+               } else {
+                       return true;
+               }
+       }
 
        FILE *f = fopen(pidfilename, "r");
        if(!f) {
@@ -751,6 +762,8 @@ static bool connect_tincd(bool verbose) {
        if(connect(fd, res->ai_addr, res->ai_addrlen) < 0) {
                if(verbose)
                        fprintf(stderr, "Cannot connect to %s port %s: %s\n", host, port, sockstrerror(sockerrno));
+               close(fd);
+               fd = -1;
                return false;
        }
 
@@ -762,6 +775,8 @@ static bool connect_tincd(bool verbose) {
        if(!recvline(fd, line, sizeof line) || sscanf(line, "%d %s %d", &code, data, &version) != 3 || code != 0) {
                if(verbose)
                        fprintf(stderr, "Cannot read greeting from control socket: %s\n", sockstrerror(sockerrno));
+               close(fd);
+               fd = -1;
                return false;
        }
 
@@ -770,6 +785,8 @@ static bool connect_tincd(bool verbose) {
        if(!recvline(fd, line, sizeof line) || sscanf(line, "%d %d %d", &code, &version, &pid) != 3 || code != 4 || version != TINC_CTL_VERSION_CURRENT) {
                if(verbose)
                        fprintf(stderr, "Could not fully establish control socket connection\n");
+               close(fd);
+               fd = -1;
                return false;
        }